1. Field of the Invention
The present invention relates generally to optical fibers, and more specifically to multimode optical fibers.
2. Technical Background
Multimode (MM) fibers that operate at the wavelength range centered around 850 nm are known. The bandwidth (BW) of these multimode (MM) fiber is limited mostly by inter-modal chromatic dispersion. To minimize the inter-modal chromatic dispersion, MM fibers are designed with graded index α-profiles. Current high bandwidth (>1 GHz·Km) optical fibers are optimized for use at 850 nm. Some of these MM fibers also have a second operating window, with lower BW (<1 GHz·Km) centered at 1300 nm.
However, some of the limitations of the optical systems that operate at 850 nm and their corresponding of optical fibers nm are: high attenuation (>2 dB/Km), high fiber dispersion (<−90 ps/nm/km), difficulties in producing high bandwidth fiber in manufacturing, and difficulties at achieving high BW fibers at multiple wavelengths.
VCSELs being developed for wavelengths greater than 900 nm for high speed operation and their use provide significant advantages over the 850 nm VCSELS. VCSELs that operate above about 900 nm and below 1250 nm are now available. Some of the advantages for utilizing these longer wavelength VCSELs include supporting Class 1 eye safety specifications, improved source and detector performance, lower optical fiber attenuation, better photon energy conversion, less VCSEL temperature increase, and lower cost. While these VCSELs are being proposed for high speed applications in the 900-1250 nm wavelength range, optical fibers that are optimized for VCSELs at wavelengths greater than 900 nm have not been designed.